Deprecation of AS_SET and AS_CONFED_SET in BGP
RFC 9774, “Deprecation of AS_SET and AS_CONFED_SET in BGP”, is a Proposed Standard document published in May 2025 by W. Kumari, K. Sriram, L. Hannachi, J. Haas. It updates RFC 4271, RFC 5065. It obsoletes RFC 6472. The canonical text is published by the RFC Editor.
Abstract
BCP 172 (i.e., RFC 6472) recommends not using AS_SET and AS_CONFED_SET AS_PATH segment types in the Border Gateway Protocol (BGP). This document advances that recommendation to a standards requirement in BGP; it prohibits the use of the AS_SET and AS_CONFED_SET path segment types in the AS_PATH. This is done to simplify the design and implementation of BGP and to make the semantics of the originator of a BGP route clearer. This will also simplify the design, implementation, and deployment of various BGP security mechanisms. This document updates RFC 4271 by deprecating the origination of BGP routes with AS_SET (Type 1 AS_PATH segment) and updates RFC 5065 by deprecating the origination of BGP routes with AS_CONFED_SET (Type 4 AS_PATH segment). Finally, it obsoletes RFC 6472.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 9774 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
- RFC 9773 ACME Renewal Information Extension
- RFC 9775 IRTF Code of Conduct
- RFC 9772 Active Operations, Administration, and Maintenance for Use in Generic Network Virtualization Encapsulation
- RFC 9776 Internet Group Management Protocol, Version 3
- RFC 9771 Properties of Authenticated Encryption with Associated Data Algorithms
- RFC 9777 Multicast Listener Discovery Version 2 for IPv6
- RFC 9770 Notification of Revoked Access Tokens in the Authentication and Authorization for Constrained Environments Framework
- RFC 9778 IANA Considerations for Internet Group Management Protocols